WHAT IS NEW IN BLADDER CANCER IMAGING - 11/09/11
Résumé |
Carcinoma of the urinary bladder, after prostate cancer, is the most common malignant tumor of the urinary tract in men and women and accounts for 2% of all malignancies. In 1993, in the United States 52,300 cases were registered. Although this number is still increasing because of aging of the population, smoking behavior (the most important single risk factor) is also an obvious influence. For example, bladder cancer mortality has decreased since 1990 because of changes in smoking behavior in the male Dutch population for successive birth cohorts after 1930 (Liemeney LALM, Witjes JA, unpublished data). The mortality in the United States in 1993 was 9900. Bladder cancer is seen predominantly in elderly men and the male to female ratio is 4:1.
About 90% to 95% of urinary bladder malignancies are transitional cell carcinomas, and the remaining 5% to 10% consist of squamous cell carcinomas and adenocarcinomas and a small number of sarcomas and metastases from other primary tumors. About two thirds of the tumors are superficial (< pT2) and are usually papillary.15 One third of the tumors show infiltration into or beyond the muscular layer of the bladder wall.
The initial treatment and prognosis largely are determined by the depth of tumor infiltration (tumor stage); the presence of positive lymph nodes and distant metastases; and the histologic tumor type.14 Therefore, exact staging is imperative. To describe local tumor extension (T), presence of lymph nodes (N), and distant metastases (M), the Union Internationale Contre le Cancer proposed a uniform clinical staging method (Fig. 1 and Table 1)14 Table 1 also presents the American classification, known as Jewett-Strong.14
In superficial tumors, those without muscle invasion (stage Ta, T1, or carcinoma in situ), patients are treated with local endoscopic resection with or without adjuvant intravesical instillations. Patients with a tumor invading the muscle layer of the bladder wall or with only minimal perivesical extension (stage T2, T3a, or minimal T3b) are selected for radical lymphadenectomy and cystectomy or radiotherapy after neoadjuvant chemotherapy. If the local tumor is in an advanced stage (stage T3b, T4a, or T4b), or if nodal or distant metastases are present, the initial treatment is palliative chemotherapy or radiation therapy. If in such a patient adjuvant surgical therapy is considered, monitoring the response to chemotherapy or radiotherapy and determining the final outcome are important.
Because clinical staging is not reliable for determining tumor extension beyond the bladder wall,12, 14 other methods are needed. In the field of imaging, rapid changes occur. After the development of CT scanning and ultrasonography, MR imaging has matured. Since the introduction of this technique, several reports in the late 1980s and early 1990s showed the superiority of this technique for staging urinary bladder carcinoma.2, 3, 7, 8, 9, 11, 12, 13, 15, 16, 17, 18, 23, 25, 31 Even now, the end of rapid technologic improvements in MR imaging is not in sight, and visualization of the bladder and of bladder carcinoma is expected to improve still further. This article describes the appearance of MR images of the normal and abnormal urinary bladder. The role of MR imaging in staging this disease and in monitoring therapy is reviewed and illustrated. Finally, the authors present an overview of current and future applications of this technique.
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| Address reprint requests to Jelle O. Barentsz, MD, PhD Department of Radiology University Hospital Nijmegen PO Box 6101 6500 HB Nijmegen The Netherlands |
Vol 24 - N° 3
P. 583-602 - août 1997 Retour au numéro
Article précédent
- ACUTE URINARY TRACT OBSTRUCTION : Imaging Update
- Susan L. Koelliker, John J. Cronan
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- Melvyn Korobkin, Isaac R. Francis
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